The present invention relates generally to dual port antenna systems, and more specifically to reducing the interference between connected transceivers.
In recent years there has been an intense effort to provide increased functionality of mobile personal computing systems while at the same time decreasing the size of such systems. This has led to a desire to incorporate two transceivers within small computing systems such as notebook computers or PDAs. For example one transceiver may be used to provide a wireless connection between a laptop and a printer or mouse while another transceiver may be used to provide a wireless Ethernet (network) connection. The problem with having two transceivers in the same mobile computing device is that if the two transceivers are collocated with their antennas closely coupled, they will interfere with each other. This means that a portion of the power from one transceiver will enter, and interfere with, the other transceiver. For example, when the Ethernet connection is transmitting it may disrupt the wireless mouse connection and vice versa.
Various designs are being considered to electrically isolate the transceivers. Today, typical levels of electrical isolation in laptop devices are in the range of, approximately, 15-20 db. This is a measure of the relative signal strength of one transmitter received by, and impacting the performance of, the other transceiver. An isolation of 15-20 db indicates that about 1-2% of the power from one transceiver is interfering with the operation of the other transceiver.
This level of isolation is not sufficient to allow acceptable operation of both transceivers. In order for both transceivers to function properly, a level of isolation between the transceivers of approximately 35-40 db may be required.